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How To Insulate Floors

How To Insulate Floors

By: Todd Bryson Pacific Insulation Supply

Proper insulation to your home ensures protection against cold breezes that may come with winter and rainy seasons, and from losing heat within your home to gaps in insulation or low-quality insulation. Some of the areas of your house that should be insulated are the floors and windows – those areas that need more attention than others, especially wooden floors and older architecture

How do you Insulate Floors?

There are multiple ways you can insulate the floors of a home, so you will have to base your insulation method on

  • Your local climate
  • Type of floor
  • Age of the home

Generally, you will need to place your insulation between the joists of the floor, and, depending on your floor, this can be applied either from underneath in the crawlspace or from above by lifting up floor panels. You can use cellulose insulation, wood-fiber insulation, or other alternatives based on your type of flooring.

Whether you’re looking for temporary fixes, or are planning to hire a licensed professional for this work, below you’ll some effective and even cheap alternatives to protecting your home against winter chills and heat loss.


How to Insulate the Floor to a Crawl Space

When you’re preparing to insulate your crawl space, you need to take into account your local climate and take a peek under your house. The condition of the insulation here will clue you in to your need for insulation: Damp, hanging insulation is a red flag and a sign that your insulation is outdated and in need of replacement. Check on the laws that apply to the area in which you are working:

The U.S. Department of Energy currently recommends insulation with an R-value of at least R-9 in floors. This is important to know, especially for homes that were built in or before 1990, as these homes may not have any insulation at all (it wasn’t required).

In moderate or dry climates that do not pose the threat of sustained freezing temperatures, it is best to install insulation between floor joists. Where the winter temperatures are extreme, it is better to opt for insulating the walls and sealing off the crawlspace entirely.

Six-inch R-19 fiberglass batts that are installed between floor joists, along with moisture control and mold prevention, will be best for winter climates with temperatures that do not drop below freezing.

Steps for Insulating a Crawl Space for Moderate Climates

  • Calculate the ventilation your crawl space will need and cut in new vents as necessary. Use spray foam insulation to seal any holes for electrical wiring and plumbing.
  • When using fiberglass batts, they should be unfaced and installed so that they are in contact with the underside of the subfloor.
  • Place wood lath every 18 inches or a crisscross webbing of wire for reliable batt support. Avoid stay rods (also known as tension rods). These compress the fiberglass and lessen the value of the insulation and can come loose.
  • Lastly, you’ll need to insulate the plumbing pipes and HVAC ducts to prevent heat loss and freezing.

How to Insulate Old Floors

Older homes will be a bit trickier to insulate because standards from decades ago were extremely different standards for architecture and home structure. The floor is one of the places in the home where a significant amount of heat escapes, whether directly into the ground or through a cold cellar located beneath.

Not only does it make the home itself much colder, but it also makes the floor uncomfortable to walk on. Proper insulation can improve the efficiency of the flooring, allowing it to hold heat in for longer periods of time and protect your home from moisture.

Floors are constructed in two ways: they are either suspended or solid. Suspended floors consist of floorboards nailed to joists, which are often carried on “sleeper” walls of brick.

  • For suspended floors, it is essential that the underside of the floor is ventilated to avoid the collection of moisture. For these floors, grilles are incorporated at the base of the walls to allow for a cross draught.
  • Solid floors, on the other hand, many of which are brick, tile, or stone, used to be laid directly onto the soil, sometimes lined with a bed of lime mortar or sand underneath. Because of this, these floors can be quite cold to the touch and difficult to insulate.

Steps for Insulating a Suspended Timber Floor

When insulating a suspended floor, the two priorities you must keep at the forefront of your mind are the improvement of thermal insulation and draughtproofing. Having access to the floor from underneath via a crawl space or cellar will make the insulation process easier.

The best way to insulate a suspended floor is to push quilt-type insulation between the joists from below. This will be supported by plastic garden netting, and additional insulation can be provided by the tongue-and-groove wood-fiber board by fixing it to the undersides of the joists.

If you don’t have a crawl space or another method of reaching the suspended floor from underneath, it is still possible for you to add insulation, but it will just require a little more creativity. You will have to lift the floorboards, a few at a time. Lay garden netting over the joists to form troughs and lay quilt insulation between the joists to fill the spaces.

You can also use a breathable membrane and then fill the troughs with cellulose insulation, or use foil-faced foam or wood-fiber insulation board between the joists supported on timber batts.

How to Insulate Wood Floors

It is especially important with wood floors to protect against excessive moisture, because wood, as you know, warps when exposed to too much water or water vapor. Because of this, creating and maintaining a vapor barrier is vital to the integrity of your wooden floor.

Unfaced batts are the best for use on wooden floors because this type of insulation doesn’t have rigid ends, but it is harder to keep up. Any loss of integrity will damage the water vapor barrier and weaken the vapor barrier and expose the floor to ground moisture.

The batting can be held in place with thin metal rods known as “lightning rods.” You should space the rods evenly, 18 inches apart to hold the insulation in place. You can also use plywood or lattice boards, but it is debatable whether the increased price is worth the slight improvement in quality. It is not suggested to use netting for the insulation of the wooden floor.

How to Go About Insulating Your Floors

When you are planning to insulate your floors, it is important to recognize that, although there are many DIY options to insulation, it is vital that you plan ahead and have the correct safety equipment. This is because there are many aspects that go into the planning and execution of an insulation project, having to take into measurements and calculations, age of the home, local building laws, and much more.

More Insulation Tips

How to Insulate Floor to Ceiling Windows

Insulating the windows and floors of your home is key to maintaining comfort in your home during winter seasons. Proper insulation to your windows will also help to cut down your energy bill by reducing the demand on your heater in these chilly times. There are a few different ways to approach insulating your windows:

Insulation Film

This is a cheap option, yet still effective when it comes to keeping the cold out of your home. Window insulation kits are readily available at most hardware stores and you’ll just need to use them indoors. These are especially useful for glass panels that are a part of either doors or windows.

The disadvantage of using insulation film is that they give off a very cloudy aesthetic, so you may want to be choosy when it comes to where in your house you’re going to apply this.

Cellular Shades

These are another great way to keep cold breezes out and protect your home against heat loss. Cellular shades are easy to install and will work for an extended period of time. Another great benefit to the cellular shade is that you can custom order them to the measurements of your home.

Double-Glazed Windows

Your doors and window frames need to be made of high-quality wood are the best long-term solution. Having double-glazed windows creates a strong quality of insulation due to the layer of gas between the two glass panels. When the wooden frame and double-glazed window work together, this creates a highly dependable source of protection against colder temperatures and winter breeze.

Layered Curtains

This, of course, is not an option to be used on its own. You should absolutely use layered curtains along with proper insulation, as any breeze that will be let in by the windows will not be prevented by the curtains, only redirected.
Adjusting the material, thickness, and the number of layers to your curtains will influence the effectiveness of the curtain and amount of heat you will be protected from.